All hospitals have rooms with vent systems with either positive or negative air pressure to isolate contagious with patients and protect sterile environments.
Also, rooms have UV sterilizers, I’m not sure if all hospitals do that. The one I worked at did.
Many hospitals have rooms that can be converted to an ICU. The problem is that hospitals are always understaffed. Always.
Also different hospitals have different capacity. For example, Texas has 400 hospitals, but 200 of them are rural with less than 4 physical rooms. Other hospitals have hundreds of rooms. 3 Covid patients, 1 non Covid patient in a 4 bed hospital will be 75% Covid at 100% capacity.
Of course a rural hospital will send a seriously ill person to a big city hospital ICU. So big city hospitals are full of ICU patients from across city and sometimes across the state.